Mixtures of alkoxylated diphenyl monohalo phosphates phenyl, dihalo phosphates, and triphenyl phosphates as motor fuel additives

ABSTRACT

Reaction mixtures of alkoxylated diphenyl monohalo phosphates and alkoxylated phenyl dihalo phosphates are used as additives, particularly as surface ignition suppressors in motor fuels. The mixtures are especially useful since they can be used in the unresolved form.

United States Patent Sung et al.

[451 Apr. 25, 1972 m1 MIXTURES 0F ALKoxYLATEn DIPHENYL MONOHALO PHOSPHATES PHENYL, DIHALO PHOSPHATES, AND TRIPHENYL PHOSPHATES AS MOTOR FUEL ADDITIVES I 72] Inventors: Rodney L. Sung, Fishkili; Kenneth L.

Dllle; Stanley R. Wappingers Falls, all of NY.

[73] Assignee: Texaco Inc., New York, N.Y.

[22] Filed: Apr. 27, 1970 [2 l] Appi. No.: 32,338

[52] U.S.Cl.... [5 1] int. Cl. ..C10l l/26,C10l 1/30 [58] Field of Search ..-....44/69, 69 P, 76; 260/977 [56] References Cited UNITED STATES PATENTS Newman et al ..44/69 Primary ExaminerDaniel E. Wyman Assistant Examiner-W. J. Shine Attorney-Thomas H. \Vhaley and Carl G. Reis [57] ABSTRACT 3 Claims, No Drawings MIXTURES F ALKOXYLATED DIPHENYL MONOIIALO PHOSPHATES PI'IENYL, DlI-IALO PI-IOSPI-IATES, AND TRIPI-IENYL PIIOSPI-IAT ES AS MOTOR FUEL ADDITIVES This invention relates to additives useful in enhancing the performance of motor fuels in internal combustion engines and to the preparation of these additives.

More particularly, this invention concerns the preparation of mixtures of monohaloalkyl diphenyl phosphates and bis(halo alkyl) phenyl phosphates which, in their unresolved form, can be added to motor fuels to improve characteristics such as surface ignition.

In this application, including the appended claims, the term motor fuel" is used to designate all liquid hydrocarbon fuels suitable for use in internal combustion engines of all types including conventional automobile engines. These fuels include those of the so-called gasoline and kerosene type as well as their mixtures. Fuels of this type are composed of a mixture of various types of hydrocarbons boiling within the range of about 80 to 800 F.

Surface ignition has been defined as the ignition of the fuelair mixture by a hot surface other than the spark plug discharge prior to the arrival of the normal flame front generated by the spark plugs. It is well recognized that undesirable effects derived from this type of ignition are loss of power, engine roughness and possible destruction of engine parts.

Within recent times various organic phosphorus compounds have been proposed for motor fuel compositions for various purposes including load-carrying additives, scavengers, surface ignition suppressors and the like. Unfortunately, despite extensive art advocating the use of phosphorus organics as additives (see for example U.S. Pat. Nos. 2,291,442, 2,889,212 and 2,892,691) their use in commerce has been largely restricted because of their propensity in many instances to depress or destroy octane'numbers by as much as from one to about four octane numbers. This tendency of many organic phosphorus compounds to have high anti-knock destruction (AKD) values was referred by us in our corpending application, Ser. No. 684,97 1 ,filed in the United States Patent Office on Nov. 22, 1967, now issued as U.S. Pat. No. 3,560,174.

In the above-noted case it was disclosed and claimed that particular organic phosphorus compound, 2-chloroethyl diphenyl phosphate having the structure given below:

0 (Gai -0 (CH1): Cl

relatively uncommon and desirable.

Quite unexpectedly during the course of synthesizing 2- haloalkyl diphenyl phosphates, it was found that unresolved reaction mixture containing a large proportion of the 2-haloalkyl diphenyl phosphates with lesser amounts of the bis-(2- haloalkyl) phenyl phosphates and the triphenyl phosphates exhibit significantly greater surface ignition suppression than does the 2-chloroethyl diphenyl phosphates. Further, the mixture of these phenyl phosphates have relatively minimal depreciating effect on octane numbers, as does the purified 2- chloroethyl diphenyl phosphate described supra. Inasmuch as these results are reproducible and the phenyl phosphate mixture can be used as ignition suppression additives in the unresolved form, the invention in both its compositional and process aspect represents a useful contribution to the art.

In view of the above discussion it is an object of this invention to provide a novel mixture of halogenated and nonhalogenated monoand diand triphenyl phosphate additives possessing high surface ignition suppression combined with relatively low anti-knock propensities, when incorporated into motor fuel compositions including gasoline.

Another object of this invention is to provide an inexpensive method of preparing said highly active additive mixture using readily available starting materials and conventional preparative techniques.

Further objects will suggest themselves to those familiar with 'the motor fuel additive art after a perusal of this disclosure.

In its broadest process aspect, mixtures of alkoxylated phenyl halo phosphates having utility as motor fuel additives are prepared by contacting mixtures containing diphenyl monohalo phosphates, phenyl dihalo phosphates and triphenyl phosphates at moderate temperatures, in the presence of a catalytic quantity of an alkoxylation catalyst, and at least a stoichiometric quantity of one or more alkylene oxides, until said desired mixture of alkoxylated phenyl halophosphates are prepared.

In the favored process embodiment, mixtures of alkoxylated phenyl monoand dihalo phosphates having utility as surface ignition suppressors are prepared by contacting substantially anhydrous mixtures containing diphenyl monohalo phosphates, phenyl dihalo phosphates and triphenyl phosphates at temperatures ranging from about 0 to 50 C., in the presence of a catalytic quantity of a catalyst selected from the group consisting of iron filings and anhydrous aluminum halides, with at least one alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide and their mixtures, said alkylene oxide being present in an excess over what is required by stoichiometry to convert said mixture of diphenyl monohalo phosphates and phenyl dihalo phosphates to their alkoxylated derivatives, until said alkoxylated mixtures are formed.

In the preferred practice, mixtures of ethoxylated phenyl halo phosphates having utility as surface-ignition suppressors in gasoline motor fuels are prepared by contacting an unresolved reaction mixture of diphenyl monochloro phosphate, phenyl dichloro phosphates and triphenyl phosphate, at temperatures ranging from about 30 C to 30 C, in the presence of a catalytic quantity of anhydrous aluminum chloride, with ethylene oxide, until said mixture of ethoxylated diphenyl monochloro phosphate and ethoxylated phenyl dichloro phosphate is prepared, said ethylene oxide being present in a 10 to 25 percent excess over what is required by theory for complete ethoxylation.

In order to supplement this disclosure more fully the following additional information is submitted:

A. Non-aqueous Environment The reaction media employed as starting material for the alkoxylation must be substantially anhydrous in order to produce the alkoxylated product mixture in good yield.

B. Contents of Mixture Employed as Starting Material The mixture in question contains as essential ingredients phenyl dihalo phosphates such as the phenyl dichloro phosphate and/or phenyl dibromo phosphate, diphenyl monohalo phosphate such as diphenyl monochloro phosphate and/or diphenyl monobromo phosphate, as well as triphenyl phosphate. Phenyl as defined herein refers to the aromatic radical C I-I While synthetic mixtures of these components may be employed as substrates for alkoxylation, the preferred mixture is preferably derived from unresolved reaction mixtures comprising from about 53 to 63 parts by weight of diphenyl monochloro phosphate, from about 5 to 15 parts by weight of phenyl dichloro phosphate and about 22 to 32 parts by weight of triphenyl phosphate. These mixtures are preferred because they are readily prepared at relatively low temperatures between about to C., when phenol is contacted with a phosphorous oxyhalide such as P'OCL or POBr in anhydrous media preferably in the presence of inert carrier gases such as nitrogen, helium, argon, etc.

C. Alkylene Oxides The alkylene oxides which are most satisfactory for alkoxylation are ethylene oxide, propylene oxide and/or mixtures of these alkylene oxides. These oxides are used in quantities sufficient to convert the diphenyl monohalo phosphates and phenyl dihalo phosphates to the corresponding alkoxylated derivative. Wen ethylene oxide is the alkylene oxide employed, from one to two moles of oxide per total moles of halo and dihalo phosphate present are used. Preferably a 10 to 25 percent excess of ethylene oxide over what is required by theory for complete ethoxylation is employed.

E. Ethoxylation Catalyst To assure optimization of yield at least one ethoxylation catalyst such as the anhydrous aluminum halides (i.e. aluminum chloride and/or aluminum bromide) or iron filings should be present. The quantity of catalyst required will vary somewhat, dependent upon the catalyst employed, the alkylene oxide and the reaction temperature. Ordinarily from 1 to 2 parts by weight of catalyst per total parts by weight of phenyl and diphenyl dihalo and halo phosphate is used. When ethylene oxide is used as the alkoxylation agent and anhydrous aluminum chloride is the catalyst, the catalyst will preferably be present in amounts ranging from 1 to 2 parts by weight of catalyst per part by weight of total phenyl and diphenyl chloro phosphate.

F. Reaction Temperatures The alkoxylation is ordinarily run at low to moderate temperatures ranging from about to 50 C. Inasmuch as the best yields are obtained at temperatures ranging from 20-30 C., these represent the preferred temperature.

G. Reaction Pressures Ordinarily the alkoxylation is run at atmospheric or nearly atmospheric pressures. Higher pressures can be employed but no advantage appears to accrue from their use to justify the added cost of pressurized equipment.

H. Reaction Time The reaction time is a variable depen dent upon reaction conditions such as temperature, pressure, mole ratio of reactants, etc. Generally the reaction time can range from one-half to 6 hours or more. When ethylene oxide is used at temperatures between about 20-30 C. ethoxylation is ordinarily complete within 1 to 4 hours.

I. Formulation of the Mixture of Ignition Additives Ordinarily the phenyl phosphate mixture of this invention is incorporated into motor fuels, preferably fuels in the socalled gasoline boiling range which contain or will contain alkyl lead compounds in amounts usually ranging from 0.5 ml to about 5 ml per gallon of fuel. However, the mixture of phenyl phosphates can be incorporated into unleaded gasolines if desired. In addition to the major amount of hydrocarbons and minor amounts of the alkyl lead compounds and the inventive phenyl phosphate mixture, the motor fuel compositions may also include one or more ingredients such as lead scavengers, gum inhibitors, lubricants, rust inhibitors, metal deactivators or other special purpose additives. These additives are normally incorporated into the gasoline base using the usual blending and mixing devices known in the art.

.I. Evaluation of Additive Mixtures l. AKD The anti-knock destructive value of the additive mixtures is determined using the Paired Rate Method." A base fuel containing tetraethyl lead has its octane number determined by both the Research Octane Number (RON) method using ASTM-D908 and the Motor Octane Number (MON) method according to ASTM D357. Sufficient amounts of the novel reaction mixture containing 2-haloalkyl diphenyl phosphate, bis( 2'haloalkyl) phenyl phosphate and triphenyl phosphate (based upon the phosphorous content of the phosphate mixture) are added to the base gasoline to provide a concentration of 0.4 theory. The average difference in octane ratings obtained in triplicate runs is the AKD. This data appears in Table 1.

2. Surface Ignition Suppression To determine surface ignition suppression in this invention, a base fuel containing 40 percent by volume aromatics and 3 ml of tetraethyl lead having a Research Octane Number of 101.4 and a Motor Octane Number of 91.3 is tested for its surface ignition effectiveness in a 11.321 compression ratio cylindrical wedge single cylinder engine. The engine is operated continuously on the base fuel during which time the engine operation was alternated between a 50 second idle cycle (600 rpm) and a second full throttle (900 rpm). The surface ignition count is obtained using an ionization gap (spark plug) as a surface ignition pick-up coupled to a recording counter device. The surface ignition rate is expressed as the number of counts per hour, the lower the count value the better t he surface ignition performance of the fuel. As shown in Table 2 the base fuel gave 196 surface ignition counts per hour. The comparative number of counts per hour noted by the addition of the additive mixture or individual additive, has been found to give a valid measure of the surface ignition suppressive activity of the additive tested.

In order to present the most detailed description of this invention possible the following examples are provided. Unless stated otherwise all parts on percentages are by weight rather than volume.

EXAMPLE 1. PREPARATION OF ETI-IOXYLATED STARTING MIXTURE OBTAINED IN EMBODIMENT A.

In a appropriate reaction vessel comparable to that described in A, a reaction mixture prepared analogously to the preparation of A, which comprises 49 parts by weight of a mixture having 61.8 percent by weight of the diphenyl monochloro phosphate, 15.4 percent by weight of phenyl dichloro phosphate and 21.9 percent by weight of triphenyl phosphate, is treated in the presence of 1 part by weight of aluminum chloride with a 10 percent excess of ethylene oxide over what is required by stoichiometry to convert the diphenyl monochloro phosphate and phenyl dichloro phosphate to their corresponding ethoxylated derivative. The reaction temperature is kept at 25 C. and the addition is completed in 2 hours. Water and diethyl ether are added to decompose the aluminum chloride. The resulting emulsion is filtered and dried with anhydrous sodium sulfate. The mixture by nuclear magnetic resonance analysis is found to contain 58 percent by weight of 2-chloroethyl diphenyl phosphate, 15 percent by weight of bis (2-chloro-ethyl) phenyl phosphate and 27 percent by weight triphenyl phosphate. The AKD values of the inventive mixture and the base fuel are shown in Table 1 and the surface ignition values of the mixture and separate components are shown in Table 2.

TABLE 1.AKD DETERMINED BY PAIRED RATE METHOD As can be seen by the above values, only minimal AKD can be attributed to the inventive mixture.

TABLE 2 Surface Ignition Rate Values (Counts/Hr) Additive Fuel Mixture Average Surface Ignition Tested Rate (counts/hr) Base Fuel (BF) 196 BF 0.4T 2 chloroethyl diphenyl phosphate I45 BF 0.4T of Inventive Mixture of Example 1 62 As can be seen by an inspection of the above values, the mixture has a much lower surface ignition value than does the base fuel or the purified 2-chloroethyl diphenyl phosphate.

As the preceding specification, including examples, demonstrate, several advantages accrue from the practice of this invention both in the process or compositional aspect. For example, the inventive process provides a novel procedure for preparing a mixture of alkoxylated phenyl phosphates having superior activity as fuel additives without the time and expense of resolving the individual components. Further, the procedure lends itself to well known techniques and employs low to moderate temperatures and atmospheric pressure.

In the compositional aspect the invention is similarly advantageous. For instance, not only are the unresolved reaction mixtures more readily and inexpensively made, but the resultant mixture of phenyl phosphates is significantly more active in ignition suppression than are the individual components of the mixture.

In addition to the above advantages, the invention is also comparatively flexible in that changes and substitutions can be made in the choice of reactants, catalysts and reaction conditions without departing from the inventive concept. However,

the metes and bounds of this invention can best be ascertained by reading the claims which follow in conjunction with the specification.

What is claimed is l. A gasoline composition consisting of a major portion of hydrocarbons within the boiling range of gasoline, aminor amount of tetralkyl lead antiknock additive and between about 0.2 to about 0.4 theory of a mixture comprising:

a. from about 53 to 63 parts by weight of diphenyl monohaloalkyl phosphate, b. from about 5 to 15 parts by weight of phenyl bis(haloalkyl) phosphate, and c. from about 22 to 32 parts by weight of triphenyl phosphate. 2. The composition of claim 1- wherein the halogenis chlorine.

3. The composition of claim 2 wherein the diphenyl monohaloalkyl phosphate is 2-chloroethyl diphenyl phosphate, the phenyl bis(haloalkyl) phosphate is bis(2chloroethyl) phenyl phosphate and the triphenyl phosphate is triphenyl phosphate 

2. The composition of claim 1 wherein the halogen is chlorine.
 3. The composition of claim 2 wherein the diphenyl monohaloalkyl phosphate is 2-chloroethyl diphenyl phosphate, the phenyl bis(haloalkyl) phosphate is bis(2chloroethyl) phenyl phosphate and the triphenyl phosphate is triphenyl phosphate 